Alignment in line-of-sight communication networks

ABSTRACT

Various of the disclosed embodiments relate to line-of-sight (LOS), e.g., optical, based networks. Particularly, systems and methods are provided for aligning nodes in a line-of-sight communication network with their peers. The nodes may be placed and passively aligned with one another as position information is passed between peers. The elevation indicated in the position information may be refined based upon relative barometric pressure readings between peers. In a next phase, isolated networks of nodes may be integrated with the network of nodes contacting the Internet backbone. Finally, routing algorithms may be implemented to address weather effects (e.g., fog) and congestion to optimize network service.

TECHNICAL FIELD

The disclosed embodiments relate to deployment and operation ofline-of-sight (LOS) networks, e.g., for providing wireless Internetaccess.

BACKGROUND

Modern society relies heavily upon the rapid dissemination of largeamounts of information. Whether via the Internet or via communityintranets, participation in the global community is regularly predicatedupon network connectivity. Individuals and communities that cannotaccess these networks are at a considerable disadvantage as compared totheir networked peers. Not only do disconnected communities lack accessto information and services provided by the rest of the world community,but they also generally lack the infrastructure to improveintra-community communication as well.

While the need for Internet or local network access may be great inthese communities, geographic and economic limitations may rendertypical delivery mechanisms unfeasible. Furthermore, these communitiesmay lack the financial resources to support the introduction ofhigh-bandwidth routers and access points provided by commercialconglomerates.

Accordingly, there exists a need for an economical method to introducenetwork access to communities in disparate geographic conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The techniques introduced here may be better understood by referring tothe following Detailed Description in conjunction with the accompanyingdrawings, in which like reference numerals indicate identical orfunctionally similar elements:

FIG. 1 is an in-situ image of a deployed optical network as may occur insome embodiments;

FIG. 2 is a block diagram of some components in a node as may occur insome embodiments;

FIG. 3 is three-dimensional depiction of the line-of-sight angles andranges relevant to a node as may occur in some embodiments;

FIG. 4 is a flow diagram depicting a very high-level example deploymentand operation of a node network as may occur in some embodiments;

FIG. 5 is a flow diagram depicting operations in anode-placement-planning algorithm as may occur in some embodiments;

FIG. 6 is a top-down, two-dimensional depiction of the line-of-sightangles and ranges relevant to a node during the path planning algorithmas may occur in some embodiments;

FIG. 7 is an example iteration of a node-placement-process as may occurin some embodiments;

FIG. 8 is an example iteration of the node-placement-process of FIG. 7;

FIG. 9 is an example iteration of the node-placement-process of FIG. 7depicting the effect of a holistic directional growth criterion as mayoccur in some embodiments;

FIG. 10 is an example iteration of the node-placement-process of FIG. 7depicting the effect of a greedy directional growth criterion as mayoccur in some embodiments;

FIG. 11 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments;

FIG. 12 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments;

FIG. 13 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments;

FIG. 14 is an example result of a coverage-driven growth criterion on anode-placement-process as may occur in some embodiments;

FIG. 15 is a flow diagram depicting a leaf generation process for acoverage-driven growth criterion in a node-placement-process as mayoccur in some embodiments;

FIG. 16 is an example result of a demand-driven growth criterion on anode-placement-process as may occur in some embodiments;

FIG. 17 is a flow diagram depicting a leaf generation process for ademand-driven growth criterion in a node-placement-process as may occurin some embodiments;

FIG. 18 is topological block diagram of node relations in a deployedCartesian mesh following Discovery/Alignment and Association as mayoccur in some embodiments;

FIG. 19 is topological block diagram of node relations in a deployedCartesian mesh prior to Discovery/Alignment as may occur in someembodiments;

FIG. 20 is topological block diagram depicting passive user-basedinformation propagation during Discovery/Alignment in a deployedCartesian mesh as may occur in some embodiments;

FIG. 21 is a cross-sectional perspective view of an incline upon whichnodes are placed and relative barometric readings are taken as may occurin some embodiments;

FIG. 22 is a three-dimensional perspective view of several nodes andtheir barometric readings relative to a first node as may occur in someembodiments;

FIG. 23 is a flow diagram depicting a process for orienting peer-nodesduring Alignment based upon their peers' barometric data as may occur insome embodiments;

FIG. 24 is topological block diagram depicting isolated formationsfollowing Discovery/Alignment and prior to Association as may occur in adeployed Cartesian mesh in some embodiments;

FIG. 25 is topological block diagram depicting an end ranking followingAssociation as may occur in a deployed Cartesian mesh in someembodiments;

FIG. 26 is a flow diagram depicting a local process for updating a noderanking as may occur in some embodiments;

FIG. 27 is a topological block diagram depicting a Star-networkfollowing Discovery/Alignment as may occur in some embodiments;

FIG. 28 is a topological block diagram depicting a caching topology in aCartesian-network as may occur in some embodiments;

FIG. 29 is a topological block diagram depicting a rerouting event in aCartesian-network as may occur in some embodiments; and

FIG. 30 is a block diagram of a computer system as may be used toimplement features of some of the embodiments.

The headings provided herein are for convenience only and do notnecessarily affect the scope or meaning of the claimed embodiments.Further, the drawings have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexpanded or reduced to help improve the understanding of theembodiments. Similarly, some components and/or operations may beseparated into different blocks or combined into a single block for thepurposes of discussion of some of the embodiments. Moreover, while thevarious embodiments are amenable to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and are described in detail below. Theintention, however, is not to limit the particular embodimentsdescribed. On the contrary, the embodiments are intended to cover allmodifications, equivalents, and alternatives falling within the scope ofthe disclosed embodiments as defined by the appended claims.

DETAILED DESCRIPTION General Description

Various examples of the disclosed techniques will now be described infurther detail. The following description provides specific details fora thorough understanding and enabling description of these examples. Oneskilled in the relevant art will understand, however, that thetechniques discussed herein may be practiced without many of thesedetails. Likewise, one skilled in the relevant art will also understandthat the techniques can include many other obvious features notdescribed in detail herein. Additionally, some well-known structures orfunctions may not be shown or described in detail below, so as to avoidunnecessarily obscuring the relevant description.

The terminology used below is to be interpreted in its broadestreasonable manner, even though it is being used in conjunction with adetailed description of certain specific examples of the embodiments.Indeed, certain terms may even be emphasized below; however, anyterminology intended to be interpreted in any restricted manner will beovertly and specifically defined as such in this section.

Network Overview

Various of the disclosed embodiments relate to line-of-sight (LOS),e.g., optical, based networks. Systems and methods are provided fordetermining where to place the network nodes in a geographic region,aligning the nodes with their peers, and then associating peers so as toachieve the desired network topology. Some of the disclosed embodimentsmay be used to provide Internet access to remote regions andcommunities. By combining local and holistic priorities at differentstages of the network deployment, a robust and efficient LOS network maybe formed.

FIG. 1 is an in-situ image of a deployed optical network 100 as mayoccur in some embodiments. A plurality of nodes 105 a-c may be in localcommunication with one another via LOS connections 115 a,b. Each nodemay provide network access 110 a-c, e.g. via wireless WIFI access, toits local region. Some nodes may be connected to a backbone 125, such asa fiber backbone (though other backbones are possible), that may beconnected to the Internet. While placed so as to provide a desiredaccess to the population of a community, the nodes can also be situatedso as to accommodate the presence of natural obstacles 135 and man-madeobstacles 130.

Hardware

FIG. 2 is a block diagram of some components in a node 200 as may occurin some embodiments. Power module 205 may be any suitable connection toa power source, e.g., a connection to a land-based power source (agrid-based alternating current), to a solar cell, to a battery source,to a voltage difference in a natural medium, etc. Network access module210 may be a component in the node 200 used to provide local networkaccess. For example, network access module 210 may be a WIFI wirelessaccess point, a wired Ethernet terminal, etc. Connection bay 215 mayinclude a plurality of connection modules 215 a-n for communication withpeer nodes. Connection modules 215 a-n need not be the same form ofcommunication, e.g., they may be microwave, line-of-sight optical,laser-based, radio-frequency, directional antenna systems, hardlineconnections, etc. The connection modules 215 a-n may have differentbandwidths and communication rates. Connection modules 215 a-n mayinclude both transmission and reception components and may be associatedwith a same or different peer node. Some connection modules 215 a-n maybe specifically designed for communication with a backbone. Connectionmodules 215 a-n may include individual or shared actuators for alignmentand directional transmission/reception.

Location module 220 may include one or more components used fordetermining location and/or orientation, such as a GPS reception system,a compass, an altimeter, a pressure sensor, etc. The pressure sensor maybe used to acquire relative barometric measurements as compared withpeer nodes as described further herein. Memory module 230 may includeone or more memory devices, which may be solid-state memories, hard diskmemories, etc. A cache 235 may be used for storing user-requestedinformation as discussed in greater detail herein. Peer topologyinformation 240 may include a record of peer locations, their rankingrelative to a backbone node, etc., for example as determined duringAssociation, as discussed herein. Routing information 245 may includeprotocols for sending information via different peers based upon channelconditions, traffic load, weather conditions, network load, etc. Logic250 may include operational logic to maintain connection modules 215a-n, to forward and redirect information to users, to generally maintainthe operation of node 200, etc. One or more processors 255 may be usedto run the logic 250. Though this example depicts a commonmemory-processor instruction architecture, one will readily recognizethat the described operations may be implemented using other tools,e.g., Field-Programmable Gate Arrays (FPGAs). A user interface 260 maybe included for an in-field operator or for users to interact with thenode 200, e.g., to designate its mode of operation, to configure itsposition, to receive data, etc.

In some embodiments, the connection modules 215 a-n may include abackhaul subsystem module. The backhaul subsystem may be designed tocarry a large data rate from node to node and may share a fraction ofthe capacity at each node with the access subsystem. The backhaulsubsystem link to neighboring nodes may be designed to carry largeamounts of data capable of supplying many access subsystems. This mayfacilitate the chaining of many such nodes together. In someembodiments, the nodes are seldom repositioned following deployment.There may be some small movement of a node due to buildings settling andtemperature variation but larger movements may occur when a node is tobe physically moved to another site, e.g., for environmental reasons.

The access module 210 may be designed to share connectivity with bothmobile and fixed end user devices in the area immediately surroundingthe node (and perhaps to users closer to this node than to other peernodes). The access subsystem may use wide area coverage wirelesstechnologies to connect with many end users in its vicinity. Rather thana physical fiber, the backhaul subsystem may utilize narrow beamcommunication systems (optical, RF with high gain antennas, etc.) topass high data rates to neighboring nodes efficiently and to minimizecommunication interference between other backhaul nodes.

The narrow beam technologies used for the backhaul subsystem may include(but are not limited to), RF, millimeter wave, and optical. Beamdivergences for the backhaul subsystem may be approximately 3-5 degreesfor RF systems, 1-3 degrees for millimeter wave systems, and 0.05 to 0.5degrees for optical systems, though these ranges are offered as examplesand one will readily recognize that others are possible.

Building sway, building settling, temperature drift, etc. may affect theviability of these different ranges. Such changes induced on an alignedsystem may induce small changes of a fraction of a degree. In someembodiments, this motion may be handled with small field of viewsteering technologies or aligning the devices to the beam centers suchthat the movement is within the beam divergence angle. During theinstallation process the backhaul subsystem may need to search over anangular range of 180 degrees in the X-Y plane and 30 degrees in the Zaxis to locate a nearby node to connect to.

FIG. 3 is three-dimensional depiction of the line-of-sight (LOS) anglesand ranges relevant to a node 305 as may occur in some embodiments.Depending upon the actuator configuration a node 305 may be able toorient its LOS transmitter/receiver within an LOS region 335 having arange 345. The node 305 may be able to rotate a full 360° about avertical access (i.e., yaw axis). This region may extend from a plane345 about a horizontal axis (i.e., pitch axis) to a maximum angle 320 aabove the plane 340 and a maximum angle 320 a below the plane 340.Regions 330 a,b may accordingly be excluded from the node 305'svisibility at boundaries 315 a,b. These regions are not necessarily toscale and will change with various embodiments (e.g., the region 330 amay be a null region and the zenith accessible to the node 305'svisibility in some embodiments). A radius 345 may depend upon thehardware of the node 305 and the transmission channel conditions (e.g.,humidity, interference from other sources, etc.). A window 325 mayreflect the actual region seen by the node 305 (multiple such windowsmay be present for different devices) at a given position along therange 345. The window is here seen increasing in dimensions along therange as a consequence of the divergence factor. As the window 325 maybe relatively narrow, accurate identification of neighboring peer nodepositions may be necessary if communication is to be established withthem in a reasonable period. Absent such information, the node 305 mayscan the window 325 across a region far from the peer node.

Note that the LOS ranges depicted herein may be unrelated to thewireless access ranges, radiofrequency, and/or microwave communicationmethods of other modules.

Deployment Overview

FIG. 4 is a flow diagram depicting a very high-level example deploymentand operation of a node network as may occur in some embodiments. Atblock 405 the node placement may be determined in a simulatedenvironment. During this stage, one or more planners may identify thebest physical and logical topologies for the nodes in a given geographicand population context. Example aspects of this operation are discussedin greater detail herein, e.g., in the sections with heading“Node-Placement Planning”.

At block 410 the nodes may be physically placed in the geographicregion. A dedicated group of technicians may install the nodes, or thenodes may be established in an ad-hoc manner by members of thecommunity. For example, nodes may be mailed to participating communitymembers with instructions for their installation.

At block 415 the nodes may engage in Discovery and Alignment proceduresto locate and orient towards their peers. During this stage, the nodesmay determine the relative physical location of their nearest peers andthe orientations necessary to perform line-of-sight communication withone or more of those peers. Example aspects of this operation arediscussed in greater detail herein, e.g., in the sections with heading“Discovery and Alignment”.

At block 420 the nodes may engage in Association to determine theirtopological relation relative a backbone. During this stage, the nodesmay determine which of their neighbors they should form LOS connectionswith so as to acquire access to a network backbone. The backbone may bea connection to the Internet or to a subnetwork. These formations mayprevent node subgroups from being isolated from the backbone connection.Example aspects of this operation are discussed in greater detailherein, e.g., in the sections with heading “Association”.

At block 425 the nodes may perform various steady-state operations,including, e.g., routing, network management, data caching, etc.

Node-Placement Planning

FIG. 5 is a flow diagram depicting operations in anode-placement-planning algorithm as may occur in some embodiments. Atblock 505, the system may receive various target constraints. Forexample, the planners of the network may specify the maximum number ofnodes available, the desired coverage per region, prioritization ofcertain communities or areas, the iteration parameters discussed ingreater detail herein, etc.

At block 510, the particular, real-world information for a target regionmay be provided. This information may include the populationdistribution of the target region (averaged, or for different temporalperiods), the obstacles (natural and man-made) in the region, theelevation of portions of the region, the location of a backboneconnection, etc.

At block 515, the system may select the next backbone connection to beconsidered. For example, a plurality of connection points may bespecified along the backbone at regular intervals. Each point may affordvarious benefits and/or drawbacks. For simplicity of explanation,consideration of a single backbone connection at a time is discussedhere, but one will readily recognize that the discussed methods may beextended to approaches in some embodiments where multiple backboneconnections are considered simultaneously.

At block 520, the system may perform an iteration among the leaves ofthe presently considered backbone. Initially, there may be only a singleleaf (the backbone connections), but proposed peers will be generatedduring this step based on various of the provided parameters. Theseproposed peers may themselves serve as leaves during a subsequentiteration to generate additional peers/leaves.

At block 525, the system may determine if a stop condition has beenreached. For example, where each of the contemplated paths has exhaustedthe maximum available number of nodes, the system may conclude thegeneration process. Similarly, if a desired level of coverage werespecified and a path provides this coverage, leaves may no longer begenerated for the path. One will recognize that the system may continuegenerating leaves for those nodes associated with paths that have notyet met a stop condition, even though other paths may have met thecondition. In some embodiments, local minima may be avoided by ignoringa stop condition, but making a record of it having been met for a givenpath (this may generate a new path in itself, e.g., a subpath of thelarger path). For example, this may prevent a path that satisfies alower prioritized stop condition (e.g., preferred cost) from preventingthe generation of path satisfying a higher prioritized stop condition(e.g., desired coverage achieved).

At block 530, the system may determine if all the backbone positionshave been considered. If not, the system may generate a new series ofnodes and paths for the next backbone connection. These may beseparately considered from those generated in the previous backbone nodeiteration, or the synergies between the paths may be considered below atblock 535.

At block 535, the system may identify and record paths based upon thetarget constraints. For example, whereas the constraints may havepreviously dictated that no further leaves be generated, the constraintsare here used to “prune” the possible connections to identify thosepaths associated with the highest metric values. For example, for a treewith a branching factor of 3, wherein 5 iterations were performed, theremay be as many as 364 nodes (1+3+9+27+81+243) to consider (this ismerely an example and many more than 5 iterations may be performed, anda different branching factor than 3 may be used, in some embodiments).Of these 364 nodes, 243 nodes may be leaves (the remaining nodes beingintermediate nodes to the backbone). For each of these 243 leaves, theremay be one or more possible paths (based upon the LOS limitations forneighboring nodes) to the backbone. There may also be many subpaths fromthe intermediate nodes to the backbone. Metric determinations based onthe constraints (e.g., cost, coverage achieved, difficulty ofinstallation, etc.) may be determined for each of these paths.

At block 540, the system may determine if the desired number of pathshas been determined. If not, additional paths and their correspondingmetrics may be determined. Once the desired number of paths has beenidentified, at block 545, the system and/or human planner may select oneor more paths associated with preferred metric values. The planner mayadjust the node positions manually at block 550 to generate the finalnode topology for in-situ installation.

Node-Placement Planning—Iteration Leaf Representation

FIG. 6 is a top-down, two-dimensional depiction of the line-of-sightangles and ranges relevant to a node during the path planning algorithmas may occur in some embodiments. Although a data structure reflectingthese variables may appear in the planning system, the two-dimensionalrepresentation of FIG. 6 is merely to facilitate explanation, and onewill readily recognize that the system anticipates the three-dimensionalstructure of FIG. 3 when assessing peer-to-peer interactions.

During an iteration of the peer generation aspect of the placementprocess, the system may consider a previously-placed node 605 and itschild node 610, which is presently a leaf considered in this iteration.Here, the LOS ranges of the nodes are depicted by range circles 615 and620, although as discussed previously, the system may consider thethree-dimensional character of the ranges and limitations imposed byterrain, hardware, etc. Child node 610 was previously placed at theperiphery of node 605's LOS range. To now place one or more leavesrelative to child node 610, the system may consider a priority direction640 and span 630 with limits 625 a and 625 b. The span need not be alonga circle, but may be a line path along the periphery of whatever formchild node 610's visibility assumes. Candidate child nodes may be placedalong this span 630 in accordance with a desired branching factor.Priority direction 640 may determine the width of span 630 (e.g., basedon the distance to a weighted centroid, the variance about the weightedcentroid, local topology around the priority direction, etc.) and thelimits 625 a and 625 b and be generated based upon one or moreconstraints. For example, where the system seeks to service a maximumnumber of communities, the system may identify centroids in thepopulation density, weight the centroids by priority and then determinethe priority direction 640 based upon the relationship between theposition of child node 640 and the weighted average (in this example,the weighted average would be in the direction of the top of the page).

Node-Placement Planning—Example Iterations

FIG. 7 is an example iteration of a node-placement-process as may occurin some embodiments. Population density data may have indicated thatcommunity members frequent regions 705 a-e. Some of these regions 705b-e, e.g., an office complex or downtown center, may be grouped closelytogether. Other regions 705 a may be isolated, e.g., depicting isolatedvillages, service stations, etc. Elevation data may indicate that alarge mountain 710 is present in the region.

Given this particular, real-world information for the target, the systemmay seek to identify an optimal node placement providing network accessto the various regions, beginning from a backbone 730. A connectionpoint 725 may serve as an initial node in the contemplated network. Inthis example a first node 715 a, has been placed within optical range ofthe connection point 725. In this simplified example, the system hasidentified the priority direction 740, e.g., based upon a desire toservice the community reflected by regions 705 b-e. For each leafgeneration iteration, the system may also iterate across differentconstraint profiles to consider different priority directions 740(though, for simplicity, only one direction is consideredhere—considering multiple priority directions at each iteration maygenerate many more than the 364 nodes presented in the example above).

FIG. 8 is an example iteration of the node-placement-process of FIG. 7.Here, for a branching factor of 3, the system has placed three new leafnodes 815 a-c. As indicated, each of these leaf nodes 815 a-c offerdifferent advantages/disadvantages. Node 815 a may ultimately provideaccess to region 705 a at lower cost than the other options. Node 815 bhowever, may provide the most direct path the regions 705 b-e. Node 815c may avoid certain limitations of elevation, but moves farther from thepopulated regions.

FIG. 9 is an example iteration of the node-placement-process of FIG. 7depicting effects of a holistic directional growth criterion as mayoccur in some embodiments. For example, leaves have been generated foreach of node 815 a-c in accordance with the constraints and consequentpriority directions 930 a-c. The priority directions 930 a-c need not bethe same (though they are in this example) and may vary in a “greedymanner” depending upon how the constraints interpret the current node'ssituation. In this example, the new leaf nodes 915 a-c, 920 a-c, 925 a-chave been generated pursuant to a “holistic” priority to reach thelargest serviceable population, i.e., regions 705 b-e.

FIG. 10 is an example iteration of the node-placement-process of FIG. 7depicting effects of a greedy directional growth criterion as may occurin some embodiments. In contrast to the preceding example, the prioritydirections 1030 a-c have been reevaluated locally for each node 815 a-c.Here, node 815 a's potential to reach region 705 a has predominated theother constraints/priorities and the priority direction 1030 a adjustedaccordingly. Similarly, node 815 b's potential to reach regions 705 b-eand/or its ability to reach a higher elevation (and possibly childrenwith greater LOS range) has predominated the otherconstraints/priorities. Accordingly, priority direction 1030 b has beenadjusted. In some instances, the rules governing creation of thepriority direction may consider the presence of other nodes and prioritydirections. For example, priority direction 1030 c may be generatedbecause the region to the bottom right remains unexplored by the otherpaths. Weights corresponding to different priorities may be adjustedsuch that the priority directions and consequent leaves generated witheach iteration provide a desirable diversity of path options forconsideration.

FIG. 11 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments. Node placement may continueuntil a stop condition is reached as discussed herein. The system maythen identify all the viable paths among the placed nodes and thenassign them appropriate metrics. For example, FIG. 11 depicts a pathfrom the backbone via nodes 1130 a-j to regions 705 b-e. This path mayreceive a relatively lower-valued metric as it requires a considerablenumber of nodes and fails to service the region 705 a.

FIG. 12 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments. This example path may receive ahigher relative metric value than the example of FIG. 11 as the nodes1230 a-h service all the regions 705 a-e. However, this path stillrequires a rather large number of nodes.

FIG. 13 is an example resultant path of the node-placement-process ofFIG. 7 as may occur in some embodiments. This example demonstrates thatpruning may not only remove nodes outside the considered path, but mayremove nodes within a considered path, if they are deemed irrelevant.For example, the system has discovered that placement of a node 1330 aatop the mountain 710 permits it extend its LOS range considerably. Infact, strategically placed periphery nodes 1330 b and 1330 c permit thenetwork to service each of regions 705 a-e with many fewer nodes thanthe examples of FIGS. 11 and 12.

One will recognize that the simplistic circle representing the LOS rangeof node 715 a has been used here merely to facilitate understanding ofthe more limited LOS options at the lower elevation, and is not depictedas extending reciprocally to node 1330 a atop the mountain in any ofFIGS. 7-13 despite the reciprocal LOS regions of nodes 715 a and 1330 a(reciprocal overlaps for nodes 1330 b and 1330 c with node 1330 a alsoare not depicted). Indeed, in an implemented embodiment the LOS regionsassociated with each node may be complicated three-dimensionalstructures, rather than these simple 2D circles. The planning system maydetermine that the LOS region about a node is a “blob”, rather than aportion of a geometric solid (such as a hemisphere) as a consequence ofthe local terrain. Absent terrain or weather considerations, however,the LOS region may resemble a hemisphere (or even as a sphere missingsome region in its lower hemisphere, e.g., as may be the case for node1330 a atop the mountain 710). In the example of FIG. 13, however, themountain would subtract a portion of the hemisphere LOS region aboutnode 715 a. However, the remaining portion of node 715 a's LOS region'shemisphere would still extend to the top of the mountain 710 so as toreach node 1330 a. Thus the planning system may initially assume themaximum possible dimensions of LOS region 335, and then “carve out”local obstructions, or reduce the range 345 based on aggregateconditions (e.g., regions with consistently high humidity).

Accordingly, where these descriptive examples discuss placing candidatenodes along a span 630, one will understand that some embodiments willplace candidate notes where the LOS region of the node in considerationintersects the ground plane. These points of intersection may be limitedto an angle range corresponding to the span 630. For very complicatedLOS region's the span 630 may be represented as a line path along theconsidered node's LOS region's intersection with the ground plane,rather than as an angle. The line path may be selected such that itscenter point coincides with a line extending from the considered nodeoutward in the priority direction.

At each iteration, candidate nodes may be placed based upon, e.g.: thepopulation centroids; environmental factors; permissions of land owners;power availability (solar, grid connections, etc.); access strength ofneighbor nodes. Metric evaluations may consider similar, or the same,factors.

Node-Placement Planning—Coverage-Driven

FIG. 14 is an example result of a coverage-driven growth criterion on anode-placement-process as may occur in some embodiments. In someembodiments, the planner may specify that “coverage” is to take priorityover other factors when selecting priority directions. Accordingly, thesystem may generate node placements and select paths that providemaximum coverage as depicted in FIG. 14.

FIG. 15 is a flow diagram depicting a leaf generation process for acoverage-driven growth criterion in a node-placement-process as mayoccur in some embodiments. At block 1505 the system may determine thecentroids of the uncovered regions (e.g., regions not yet beingserviced). For example, the regions may be construed as a Voronoidiagram, the centroids as the centers of the respective Voronoi region(generated, e.g., following a K-means clustering). At block 1510, thesystem may identify the direction to the closest and/or largest centroidfor a particular leaf node under consideration. At block 1515 the systemmay determine the number of leaves to generate (e.g., the branchingfactor may vary depending upon the priority). At block 1520 the systemmay determine the leaf spread and at block 1525 the system may generatethe new leaves.

Node-Placement Planning—Demand-Driven

FIG. 16 is an example result of a demand-driven growth criterion on anode-placement-process as may occur in some embodiments. In someembodiments, the planner may specify that “demand” is to take priorityover other factors when selecting priority directions. Accordingly, thesystem may generate node placements and select paths that service themaximum number of individuals.

FIG. 17 is a flow diagram depicting a leaf generation process for ademand-driven growth criterion in a node-placement-process as may occurin some embodiments. At block 1705, the system may determine thedistance to population centroids. For example, the populations may againbe grouped based upon, e.g., a K-means or similar grouping method. Atblock 1710, the system may identify the direction to the nearest/largestpopulation centroid for a leaf node under consideration. At block 1715,the system may determine the number of leaves to generate (e.g., thebranching factor may vary depending upon the priority). At block 1720the system may determine the leaf spread and at block 1725 the systemmay generate the new leaves.

Discovery and Alignment

After the planning phase has been completed, the nodes may be physicallyplaced in the region at their determined positions. Following placement,the nodes may then locate their peers and form appropriate connectionsto achieve the desired level of service identified in the planningstage. The identification of neighboring peers is generally referred toas “Discovery” herein, the orientation to a peer as “Alignment”, and theformation (via the first or subsequent orientations) of appropriateconnections as determined during planning as “Association”. For purposesof simplifying explanation, the following discussion of “Alignment”,“Discovery” and “Association” will generally be with reference to aCartesian layout, though one will readily recognize that his need not bethe case and that other layouts may occur (e.g., a “Star” network asdiscussed herein). Different layouts may be generated as a result of theplanning phase discussed above.

FIG. 18 is topological block diagram of node relations in a deployedCartesian mesh following Discovery, Alignment, and Association, as mayoccur in some embodiments. Each of the columns may have been generatedfrom a planning analysis beginning at a respective backbone connection.For example, the column comprising nodes 1815 a-c may result fromplanning iterations beginning at backbone connections 1805 b. Ascontemplated in some embodiments, and depicted in the above example,there may be 3 types of backhaul hardware: Fiber input (the connectionof the network to the trunk); high speed hardware (e.g., 100 GB); andRegular speed (e.g., 1 GB).

FIG. 19 is topological block diagram of node relations in a deployedCartesian mesh prior to Discovery/Alignment as may occur in someembodiments. While FIG. 18 generally refers to the logical relationbetween nodes (i.e., their routing connections between one another)rather than their geographic location, FIG. 19 depicts ranges 1910 a and1910 b reflecting the LOS for nodes 1815 b and 1825 b. During“Discovery”, the node 1815 b should recognize that the peer 1815 a iswithin LOS range based upon their respective locations. Similarly, thenode 1825 b may recognize that each of peer nodes 1820 a and 1825 a arewithin LOS range. As there are multiple alternatives for node 1825 b,during Alignment node 1825 b may form a default connection with either(or in some embodiments, both) of nodes 1820 a and 1825 a. These defaultconnections may be refined (e.g., supplemented or removed) subsequentlyduring Association so as to achieve a desired connection with a backbonenode.

Discovery—Passive User Propagation

In some embodiments, the nodes may determine their location informationactively, e.g., by querying a GPS system or receiving coordinates from atechnician on-site. In some embodiments, the installing technician maytake an image of the node following installation, including one or twolandmarks in the image. These landmarks may then be cross-referencedwith database images to infer the location of the node. Some embodimentsmay combine various of these disclosed techniques to infer more accurateaggregate readings.

In some embodiments, each node may also rely (in lieu of, in additionto, or in complementation with the other techniques) on the passivetransfer of information by users between its peers. For example, FIG. 20is topological block diagram depicting passive user-based informationpropagation during Discovery in a deployed Cartesian mesh as may occurin some embodiments. A user with a mobile device may move from position2010 a to position 2010 b and then to position 2010 c. Followinginstallation, each of the nodes A-F may have local network accessactivated (e.g., WIFI) even though they are not yet in communicationwith a backbone connection. Accordingly as the user passes between thedifferent nodes the user's mobile communication device may associatewith each of the nodes. For example, the user may first pass node Bwhich recognizes its GPS position as being “32.22.21| 28.22.11” (node Bmay infer these coordinates from the user device's GPS coordinates). Themobile communication device may be running an application or otherwisebe able to store this information locally in its memory in a locationlog 2015 a. When the user arrives as position 2010 b the mobile devicemay associate (e.g., form an 802.11 association) with Node C. The GPSpositions values in this example are provided merely to facilitateunderstanding and do not reflect values that might actually be used inreal-world implementations of embodiments.

Node C may pull the position log 2015 a from the mobile device, make itsown internal record of the position of Node B, and supplement the user'smobile device location log 2015 b with its own location information, aswell as any location not already present that it previously acquired.For example, had Node C previously encountered a user who had passedNode A, the location information for Node A would be included in thelocation log 2015 b. By the time the user has reached position 2010 c,the user has received and provided location information from and to eachof Nodes D, E, and F.

Thus the user/subscribers may initially be given membership (802.11authentication, etc.) to all of the node access points. For example, ina WIFI system this may be accomplished by providing a commonSSID/password or by providing open access. As each user passes by anunconfigured node the access point subsystem sends a message to theuser. The message may, e.g., contain the following information: the MACaddress of the node (or other unique identifier); GPS coordinates of thenode; Altimeter data from the node; the hardware types of the variousnode communication systems; and association information for the node(e.g., whether it is in communication with a backbone node as preferredby the planning process). The user device may store this information andsubsequently convey it to a future encountered node.

By this mechanism, people randomly moving about may carry the locationsof the nodes to the other nodes. Eventually, each node may have acomplete list of all neighboring nodes.

Alignment—LOS Search Variations

In some embodiments, during Alignment the node may perform a randomsearch with narrow beams, e.g., a small window 325. In theseembodiments, the node may use a step size of one half the beam width(e.g., width of the window 325) and a dwell-time at least twice the timeto step between two angles. For example, a beam steering system couldtake 5 ms to switch between two positions and dwell for 10 ms at eachposition. In the case of an RF beam width of 4 degrees, an angular stepsize of 2 degrees may be used. Each node would then search within90*15=1350 steps in this example. For the node to detect a neighboringnode in this example, both narrow beams may need to align which wouldtake 1.82 million steps. With each step taking 15 ms the total time toalign a pair of nodes may take 7.6 hours. A millimeter wave system witha 2 degree beam width and a step size of 1 degree may instead allow eachnode would search through 5400 steps. Detection would take 29.1 millionsteps, which would take 121 hours.

As another example, an optical system with a beam width of 0.2 degreeswith a 0.1 degree step size would require each node to search through540,000 steps. This alignment may take 291 billion steps and 138 years.The narrow beam random search approach is therefore generally consideredherein for embodiments having wider beam widths.

Some embodiments employ random searches with wider beams (e.g., largerwindow 325). For example, some node embodiments use a separate signalwith a wider beam for Alignment, but then use a narrower beam withhigher speed data during normal operation. This wider beam signal couldbe used to narrow the search area for the narrow beam to its beam width.

In some embodiments, an omnidirectional receive antenna/sensor oromnidirectional transmit antenna/source may be connected to the node.This omnidirectional device may reduce the number of search steps ofeach node to the square root of the set time as it would not requirethat each node have exactly determined its relative alignment with itspeer for the two to recognize one another.

Some embodiments implement a GPS-assisted search that may employadditional long-range wide area wireless technology. Each node may befitted with an altimeter (e.g., using the barometric approach describedherein) and GPS receiver to determine its position in space. The nodesmay then share this information with neighboring peers to aid inalignment. An additional omnidirectional radio may also be used to sharethe information. The frequency and transmit power of this radio may bechosen to allow the signal to adequately reach the nearby nodes (e.g.,as determined during the planning phase described above). Collisionavoidance techniques may be performed and could be used to share thechannel between the many nodes.

The GPS data may allow the node to confine the search region to theerror band of its position data and the error band of the peer node'sposition data. This error may range from a worst case of 8 degrees inthe horizontal plane at extremely close range (80 meters) and 1 degreein the Z axis to a worst case of 0.6 degrees in the horizontal at 10 kmand 0.006 degrees in the Z axis. This may allow for a much faster searchprocess during Alignment.

Some embodiments employ a GPS-assisted search using an access subsystem.These approaches may remove the need for an extra communication systemsolely for the purpose of alignment. For example, the access subsystemwireless range may allow the nodes to communicate directly with eachother and to relay their address and coordinate information. As thisinformation payload may be transmitted at a low data rate, it may bepossible to use a lower bit rate (fewer bits/Hz) to pass the message.

Unfortunately, the access technology's range may render the GPS-assistedsearch using an access subsystem approach unfeasible in some situations.The limited range may prevent the passage of address and coordinateinformation to the neighboring nodes. In these situations, the passivetransfer of peer information by users travelling between nodes asdescribed herein may be used instead.

Alignment—Barometric Elevation Inference

In some embodiments the nodes may be able to infer their locationexclusively from GPS information, information provided by an installingtechnician, etc. However, in some embodiments, position information maybe inferred from a plurality of sources. In some embodiments, relativepressure information may be used by the nodes to complement GPSinformation so as to achieve more accurate determinations of the nodes'relative orientations. For example, FIG. 21 is a cross-sectionalperspective view of an incline 2110 a upon which nodes 2115 a-c areplaced and relative barometric readings are taken as may occur in someembodiments. The location logs, or other information transferredpassively between the nodes, may include a barometric reading for anode. The nodes may compare the difference between their own barometricreading and the reading of a peer to infer the difference in elevation(and corresponding angle in which to scan the window). In this example,the node 2115 a is at a slightly lower elevation relative to node 2115b. Accordingly, the pressure at node 2115 a is higher than at node 2115b and a small, positive (+10) difference is noted. In contrast, node2115 c is located at a much higher elevation than node 2115 b.Accordingly, the pressure at node 2115 c is lower than at node 2115 band a large, negative (−75) difference is noted. The pressure to anglecorrespondence may be inferred from a table or determined dynamically.

FIG. 22 is a three-dimensional perspective view of several nodes 2205a-d and their barometric readings relative to a first node as may occurin some embodiments. Based on relative barometric readings and peer nodelocations relative to the terrestrial plane, each node may be able toinfer a topological mapping of its local surroundings. For example, thenode 2205 d may recognize, based e.g., on GPS coordinates, that withinthe terrestrial plane 2215 (i.e., a plane perpendicular to a linepassing from the node to the center of the Earth) it is a distance 2210a from the node 2205 a, a distance 2210 b from the node 2205 b, and adistance 2210 c from the node 2205 c. There may be a relative pressuredistance of +80, −75, and −25 for each of the respective nodes 2205 a-crelative to node 2205 d. From these differences, node 2205 d may inferrelative vertical heights 2225 a-c for each of nodes 2205 a-c. With theheights 2225 a-c and distances 2210 a-c known, the node 2205 d mayreadily infer the Euclidean distance 2220 a-c to each node and thecorresponding angle relative to the terrestrial plane 2215.

FIG. 23 is a flow diagram depicting a process for orienting peer-nodesduring Alignment based upon their peers' barometric data as may occur insome embodiments. At block 2305, the node may determine the peer nodesnearest in the terrestrial plane. At block 2310, the node may determinethe in-plane distance to the peer. At block 2315, the node may determinethe relative barometric deltas do the nearest peers and thecorresponding height values. At block 2320, the node may determine theEuclidean distance to the nearest peers. At block 2325, the node maydetermine the angle to the nearest peers. At block 2330, the node mayupdate its locally stored information regarding the nearest peers toreflect their relative positioning. At block 2340, the node may orientto the nearest peer, e.g., as part of a default connection prior toAssociation.

Association

In a system where each node has only enough communication links to reachsome of its neighboring nodes, it may be very desirable for the systemto choose the correct adjacent node to link to in accordance with thePlanning phase. If the system additionally has communication links withdifferent speeds, it may be especially preferred that the correct pairsof links (e.g., as specified in the Planning process) are established.The Association phase includes one or more processes for ensuring thatappropriate links are formed.

The transition from the Alignment process to Association may occur basedon one or more conditions, or may occur organically node-by-node as eachacquires sufficient information regarding their peers. For example, insome embodiments each node may transition from the Alignment procedureto the Association procedure after a fixed period of time, after asufficient amount of peer location information has been acquired, orupon some other signal.

Once Alignment completes, the default associations between nodes may notproperly reflect the desired, planned association. FIG. 24 istopological block diagram depicting isolated formations followingAlignment and prior to Association as may occur in a deployed Cartesianmesh in some embodiments. Isolated “island” networks 2405 a,b haveformed lacking a backbone connection, let alone the appropriate backboneconnection determined during Planning. In this example, only node 2410 ahas properly associated with backbone connection 2415 a as intendedduring Planning. While node 2410 b may recognize both nodes 2410 c and2410 a as being within LOS range, node 2410 b may have formed a defaultassociation with node 2410 c. Similar default reasoning may haveresulted in node 2410 d failing to associate with node 2415 a, node 2410e failing to associated with node 2410 f, and 2410 f with backbone 2415c. As discussed herein, the nodes within isolated networks 2405 a,b mayrecognize that they lack a connection with a backbone 2415 b. Each nodemay share path information with its peers until a path to the backboneconnection has been identified.

FIG. 25 is topological block diagram depicting an end ranking followingAssociation as may occur in a deployed Cartesian mesh in someembodiments. In this example, each node is given a two part topologicalreference, referred to herein as a rank: (X,Y). The first part of therank (X, the backbone component) represents the node's relation to thebackbone (e.g., to a high speed network devices). The second part of therank (Y, the subnetwork component) represents the node's relation toother nodes in the subnetwork (e.g., to the regular speed networkdevices). The relation may be, e.g., a number of hops from a backbonenode associated with the subnetwork. The presence of a backbone input toa node's hardware may result in the node automatically assigning itselfa rank of 0 for the backbone rank and 0 for the subnetwork rank. Forexample, initially nodes 2505 a-d may have had rank 0,0. As they begancommunication with one another, they would select unique backbone rankidentifiers as indicated. Nodes unconnected to the backbone may beginwith an arbitrary, non-zero X rank (e.g., 9999).

A node 2505 a with a hardcoded (0,0) rank may look through its list ofneighboring node coordinates and determine which nodes are closest andhave a rank of (X,0) where the X is any value (the nodes 2505 b-d willassume other X ranks as knowledge of the node 2505 a propagates). Thenode 2505 a may retain this (0,0) ranking based on a hard-codedpreference specified in the planning phase (e.g., a literal hardcodingby the installing technician, a rule established in the logic code,etc.). This node may then begin a search with its high speed opticalheads (or whatever other communications module is available to theembodiment) in the direction of the neighboring nodes.

As the location of the (0,0) ranked node propagates among the otherdevices, the other devices will begin to search in the direction of the(0,0) node using the GPS coordinates of the (0,0) node. When a nodefinds the (0,0) node it may review the ranking information to determineif it falls within the subnetwork of the 0,0 node. If so, the node 2510a may update its rank to (1,0). The distance between nodes may governthe priority of assignment, resulting in there being eventually only one(1,0) ranked node 2505 b on the backbone connected to the (0,0) node2505 a. This rank is updated in the broadcast message passed on to theneighboring nodes. Each other node with rank (X,0) then starts a searchlooking for node (1,0) until a link is made and the new node 2505 c isgiven the rank (2,0) and so on.

In a similar manner, the regular speed node links closest to node 2505 amay seek out the node with the (0,Y) where Y is any number (thepreference for X being zero again based on a total ordering associatedwith distance). Each node which has been informed of a nearby node witha (0,Y) rank may begin a search of the coordinate area around the GPScoordinates of the node. The (0,Y) node may begin a search in thedirection of the closest (X,Y) nodes. When a link is established thenode 2510 a-d updates its rank to (1,Y) and this rank is updated in themessage shared with neighboring nodes. Other nodes without associatedhardware that receive the message with a device with a (1,Y) node begina search in the direction of the (1,Y) node and the process continuesfrom there.

In the event a node determines that it has moved through a loss ofconnectivity or through a change in its GPS coordinates it may reset itsrank to the defaults and allow/cause the process to begin again.Similarly, if a node detects a node with coordinates closer than a nodeof the appropriate rank, it may infer that a new node is present, orthat a node has been moved. Consequently, the node may reset its rankallowing the search procedure to restart. Thus, in some embodiments thenode Association process may proceed generally as follows: 1) From aninitial start state (e.g., following installation or reset), every nodeselects a random rank between 1 and N where N is the number of nodes inthe network, excluding node 0. Node 0 selects rank 0; 2) Each time anode receives a location list update (e.g., from a passing person, orfrom a neighbor node) it looks through the list to identify the locationof the first known node with a higher rank and the first known node witha lower rank as given by the list; and 3) The node then attempts toconnect first to the lower rank node (i.e. closer to node 0).

In this example, if the connection is successful, the node updates itsrank to the rank of the node it connected to +1. It then attempts toconnect to the higher ranked node. If the connection to the higherranked node succeeds the node it connected to updates its rank to theconnecting node's rank+1. For example, a node (arbitrarily referred toas “Node Z”) with Y rank 5 receives a list that identifies the locationof nodes with Y ranks 0,2,8,10. Node Z first attempts to connect to thenode with Y rank 2. If the connection is successful Node Z's Y rank isupdated to rank 3. Node Z may attempt to connect to the node Y ranked 8and if successful, the node Y ranked 8 updates its Y rank to 6 instead.

FIG. 26 is a flow diagram depicting a local process for updating a noderanking as may occur in some embodiments. At block 2605, the node mayactively solicit ranking information from its peers. At block 2610, thenode may determine if the acquired ranking information includes abackbone node. At block 2615, the node may notify its peers of thedecision to adjust its ranking. At block 2620, the node may adjust itsranking. Subsequent requests for its ranking information will nowinclude this new ranking. At block 2625, the node may passively solicitranking information from its peers.

As discussed above, ranking information may back-propagate to theconnection nodes on the backbone. The backbone nodes have knowledge ofthe desired network topology and may resubmit the ranking informationinto the network so as to accord with the preferred ranking.Accordingly, at block 2630 the node may determine if a higherprioritized path has been identified, e.g., as designated by a backbonenode. If so, the ranking may be adjusted pursuant to blocks 2615 and2620. If no higher priority information has been received, then the nodemay continue to passively listen for incoming ranking information.

Network Topology Variations

FIG. 27 is a topological block diagram depicting a Star-network 2700following Association as may occur in some embodiments. The planningphase may have imposed ranking conditions such that nodes 2710 a,beither facilitate branching, or do not facilitate branching from thebackbone node. As discussed herein, branching may be suitable at pointsof high elevation (buildings, mountains, etc.) and for nodes having manydifferent communication components (e.g., more optical components andmore memory).

Data Caching

FIG. 28 is a topological block diagram depicting a caching topology in aCartesian-network as may occur in some embodiments. During the planningphase, locations may be strategically determined where heavy usage ortraffic may occur. At these strategic points, caching (or additionalcaching) memory may be provided to improve the network's efficiencyduring operation.

Routing Application

FIG. 29 is a topological block diagram depicting a rerouting event in aCartesian-network as may occur in some embodiments. For example, fog2905 may form between the nodes 2910 a and 2910 b. During the planningphase, the anticipated weather patterns may be taken into considerationand alternative routing preferences included in the distributed nodes.For example, node 2910 a may be redirected to form an optical connectionwith node 2910 c. In some embodiments this rerouting may be performeddynamically, e.g., by restarting the Association process for the nodesdisconnected from the backbone. In some embodiments, this Associationprocess may differ from the original Association and may considerrerouting guidance provided from the planning phase. Routing adjustmentsmay not only include the creation of new connections, but may insteadinclude communication module changes. For example, fog 2905 may beimpenetrable at optical wavelengths, but not a microwave wavelengths.Accordingly, nodes 2910 a and 2910 b may switch to another communicationmedium (e.g., microwave) until the condition abates.

Computer System

FIG. 30 is a block diagram of a computer system as may be used toimplement features of some of the embodiments (e.g., as may be used toperform the Planning process or as may appear in the node 200). Thecomputing system 3000 may include one or more central processing units(“processors”) 3005, memory 3010, input/output devices 3025 (e.g.,keyboard and pointing devices, display devices), storage devices 3020(e.g., disk drives), and network adapters 3030 (e.g., networkinterfaces) that are connected to an interconnect 3015. The interconnect3015 is illustrated as an abstraction that represents any one or moreseparate physical buses, point to point connections, or both connectedby appropriate bridges, adapters, or controllers. The interconnect 3015,therefore, may include, for example, a system bus, a PeripheralComponent Interconnect (PCI) bus or PCI-Express bus, a HyperTransport orindustry standard architecture (ISA) bus, a small computer systeminterface (SCSI) bus, a universal serial bus (USB), IIC (I2C) bus, or anInstitute of Electrical and Electronics Engineers (IEEE) standard 1394bus, also called “Firewire”.

The memory 3010 and storage devices 3020 are computer-readable storagemedia that may store instructions that implement at least portions ofthe various embodiments. In addition, the data structures and messagestructures may be stored or transmitted via a data transmission medium,e.g., a signal on a communications link. Various communications linksmay be used, e.g., the Internet, a local area network, a wide areanetwork, or a point-to-point dial-up connection. Thus, computer readablemedia can include computer-readable storage media (e.g., “nontransitory” media) and computer-readable transmission media.

The instructions stored in memory 3010 can be implemented as softwareand/or firmware to program the processor(s) 3005 to carry out actionsdescribed above. In some embodiments, such software or firmware may beinitially provided to the processing system 3000 by downloading it froma remote system through the computing system 3000 (e.g., via networkadapter 3030).

The various embodiments introduced herein can be implemented by, forexample, programmable circuitry (e.g., one or more microprocessors)programmed with software and/or firmware, or entirely in special-purposehardwired (non-programmable) circuitry, or in a combination of suchforms. Special-purpose hardwired circuitry may be in the form of, forexample, one or more ASICs, PLDs, FPGAs, etc.

Remarks

The above description and drawings are illustrative and are not to beconstrued as limiting. Numerous specific details are described toprovide a thorough understanding of the disclosure. However, in certaininstances, well-known details are not described in order to avoidobscuring the description. Further, various modifications may be madewithout deviating from the scope of the embodiments. Accordingly, theembodiments are not limited except as by the appended claims.

Reference in this specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the disclosure. The appearances of the phrase “in one embodiment” invarious places in the specification are not necessarily all referring tothe same embodiment, nor are separate or alternative embodimentsmutually exclusive of other embodiments. Moreover, various features aredescribed which may be exhibited by some embodiments and not by others.Similarly, various requirements are described which may be requirementsfor some embodiments but not for other embodiments.

The terms used in this specification generally have their ordinarymeanings in the art, within the context of the disclosure, and in thespecific context where each term is used. Certain terms that are used todescribe the disclosure are discussed below, or elsewhere in thespecification, to provide additional guidance to the practitionerregarding the description of the disclosure. For convenience, certainterms may be highlighted, for example using italics and/or quotationmarks. The use of highlighting has no influence on the scope and meaningof a term; the scope and meaning of a term is the same, in the samecontext, whether or not it is highlighted. It will be appreciated thatthe same thing can be said in more than one way. One will recognize that“memory” is one form of a “storage” and that the terms may on occasionbe used interchangeably.

Consequently, alternative language and synonyms may be used for any oneor more of the terms discussed herein, nor is any special significanceto be placed upon whether or not a term is elaborated or discussedherein. Synonyms for certain terms are provided. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termdiscussed herein is illustrative only, and is not intended to furtherlimit the scope and meaning of the disclosure or of any exemplifiedterm. Likewise, the disclosure is not limited to various embodimentsgiven in this specification.

Without intent to further limit the scope of the disclosure, examples ofinstruments, apparatus, methods and their related results according tothe embodiments of the present disclosure are given above. Note thattitles or subtitles may be used in the examples for convenience of areader, which in no way should limit the scope of the disclosure. Unlessotherwise defined, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which this disclosure pertains. In the case of conflict, thepresent document, including definitions will control.

What is claimed is:
 1. A computer-implemented method executed in a firstnode for aligning the first node with a second node, comprising:determining a position coordinate associated with the first node;determining a barometric pressure measurement associated with the firstnode; receiving an indication of: position coordinates associated witheach of a plurality of one or more other nodes, the plurality of one ormore other nodes including the second node; and pressure measurementsassociated with each of the plurality of one or more other nodes;determining a relative elevation based upon the pressure measurementassociated with the first node and the pressure measurement associatedwith the second node; determining a relative position based upon theposition coordinates associated with the first node and the positioncoordinates associated with the second node; and orienting aLine-of-Sight (LOS) communication device at the first node based uponthe relative elevation and the relative position.
 2. Thecomputer-implemented method of claim 1, wherein the position coordinateassociated with the first node is a GPS coordinate.
 3. Thecomputer-implemented method of claim 1, wherein determining a relativeposition comprises determining an in-plane distance, and whereinorienting a LOS communication device comprises rotating the LOScommunication device based upon an angle associated with a Euclideandistance to the second node.
 4. The computer-implemented method of claim1, wherein receiving an indication comprises receiving a wirelesstransmission from a user mobile device in proximity to the first node.5. The computer-implemented method of claim 1, wherein receiving anindication comprises receiving a transmission from a third node.
 6. Thecomputer-implemented method of claim 5, wherein third node and thesecond node are the same node.
 7. The computer-implemented method ofclaim 1, further comprising notifying a third node that the first nodeis in communication with the second node.
 8. A computer-readable storagemedium storing instructions configured to cause at least one computersystem to perform a method comprising: determining a position coordinateassociated with a first node; determining a barometric pressuremeasurement associated with the first node; receiving an indication of:position coordinates associated with each of a plurality of one or moreother nodes, the plurality of one or more other nodes including a secondnode; and pressure measurements associated with each of the plurality ofone or more other nodes; determining a relative elevation based upon thepressure measurement associated with the first node and the pressuremeasurement associated with the second node; and determining a relativeposition based upon the position coordinates associated with the firstnode and the position coordinates associated with the second node;orienting a Line-of-Sight (LOS) communication device at the first nodebased upon the relative elevation and the relative position.
 9. Thecomputer-readable storage medium of claim 8, wherein the positioncoordinate associated with the first node is a GPS coordinate.
 10. Thecomputer-readable storage medium of claim 8, wherein determining arelative position comprises determining an in-plane distance, andwherein orienting a LOS communication device comprises rotating the LOScommunication device based upon an angle associated with a Euclideandistance to the second node.
 11. The computer-readable storage medium ofclaim 8, wherein receiving an indication comprises receiving a wirelesstransmission from a user mobile device in proximity to the first node.12. The computer-readable storage medium of claim 8, wherein receivingan indication comprises receiving a transmission from a third node. 13.The computer-readable storage medium of claim 12, wherein third node andthe second node are the same node.
 14. The computer-readable storagemedium of claim 8, the instructions further comprising notifying a thirdnode that the first node is in communication with the second node.
 15. Acomputer system comprising: at least one processor; at least one memorycomprising instructions configured to cause the at least one processorto perform a method comprising: determining a position coordinateassociated with a first node; determining a barometric pressuremeasurement associated with the first node; receiving an indication of:position coordinates associated with each of a plurality of one or moreother nodes, the plurality of one or more other nodes including a secondnode; and pressure measurements associated with each of the plurality ofone or more other nodes; determining a relative elevation based upon thepressure measurement associated with the first node and the pressuremeasurement associated with the second node; determining a relativeposition based upon the position coordinates associated with the firstnode and the position coordinates associated with the second node; andorienting a Line-of-Sight (LOS) communication device at the first nodebased upon the relative elevation and the relative position.
 16. Thecomputer system of claim 15, wherein determining a relative positioncomprises determining an in-plane distance, and wherein orienting a LOScommunication device comprises rotating the LOS communication devicebased upon an angle associated with a Euclidean distance to the secondnode.
 17. The computer system of claim 15, wherein receiving anindication comprises receiving a wireless transmission from a usermobile device in proximity to the first node.
 18. The computer system ofclaim 15, wherein receiving an indication comprises receiving atransmission from a third node.
 19. The computer system of claim 18,wherein third node and the second node are the same node.
 20. Thecomputer system of claim 15, the method further comprising notifying athird node that the first node is in communication with the second node.